• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.9 no.9
• /
• pp.3432-3448
• /
• 2015

Interference can cause serious problems in our daily life. Traditional ways in localizing a target can't work well when it comes to the source of interference for it may take an uncooperative or even resistant attitude towards localization. To tackle this issue, we take the BPSN (Binary Proximity Sensor Networks) and consider a passive way in this paper. No cooperation is needed and it is based on simple sensor node suitable for large-scale deployment. By dividing the sensing field into different patches, when enough patches are formed, good localization accuracy can be achieved with high resolution. Then we analyze the relationship between sensing radius and localization error, we find that in a finite region where edge effect can't be ignored, the trend between sensing radius and localization error is not always consistent. Through theoretical analysis and simulation, we explore to determine the best sensing radius to achieve high localization accuracy.

• Transactions of Materials Processing
• /
• v.21 no.8
• /
• pp.479-484
• /
• 2012

The objective of this study is to compensate the elastic recovery in the flexible forming process using the predictive models. The target shape was limited to two-dimensional shape having only one curvature radius in the longitudinal-direction. In order to predict the shape error the regression and neural network models were established based on the finite element (FE) simulations. A series of simulations were conducted considering input variables such as the elastic pad thickness, the thickness of plate, and the objective curvature radius. Then, at sampling points in the longitudinal-direction, the shape errors between formed and objective shapes could be calculated from the FE simulations as an output variable. These shape errors were expressed to a representative error value by the root mean square error (RMSE). To obtain the correct objective shape the die shape was adjusted by the closed-loop using the neural network model since the neural network model shows a higher capability of estimating the shape error than the regression model. Finally the experimental result shows that the formed shape almost agreed with the objective shape.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2003.06a
• /
• pp.920-924
• /
• 2003

This paper on measurement of curvature radius by the using of laser interferometer and prove. Mean value compared of ball and bearing It is developed program for date creation, and the verification using program. Measurement object center and curvature radius taking of LSC. when it is compared bearing prove with ball prove, the bearing prove can not proper by reason of big uncertainty and If laser setting error decrease, curvature radius get precision radius 10$\^$-5/.

• Journal of the Korean Society for Precision Engineering
• /
• v.16 no.12
• /
• pp.174-181
• /
• 1999

This paper describes the effect of the stylus tip size on the shape error in surface topography measurement. To analyze the distortional effect of an actual surface geometry origination from the finite stylus size, the surface is modeled as a sinusoid and the stylus tip as a circle. The magnitude of this distortion is defined as the ration of standard deviation, and this is expressed as an analytic function of the stylus tip radius and the geometrical parameter of a sinusoid. In this paper, the spectrum analysis of the profile is applied to investigate the distortional effect due to the mechanical filtering of the stylus in the frequency domain. and, the cumulative power spectrum is proposed to assess the shape error of measured data according to the various stylus tip sizes. From these results, a new method to select proper stylus tip radius is proposed.

• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.11 no.5
• /
• pp.100-105
• /
• 2002

The comprehensive system analysis for contour milling operation and its error has performed in this study. The obtained experimental results were from the practical points of view. In down-milling operation the contour error curve illustrates bigger thean actual workpiece radius. The contour error increased when the cutter loads increased. Through the procedural evaluation, it could ascertain the characteristics of generation mechanics in circular contour machining error, and the weight of each factors.

• Journal of Korean Ophthalmic Optics Society
• /
• v.4 no.1
• /
• pp.7-14
• /
• 1999

The purpose of this study is to evaluate the relationship between ocular components and refractive error for human eye. Ocular components were measured by keratometry, phakometry, and ultrasonography. Refractive error was measured by subjective refraction on 38 subjects aged from 17 to 30. The results were as follows; 1) Refractive error and axial length, vitreous chamber depth, axial length/corneal radius were highly correlated that the correlation coefficients were 0.95, 0.96, 0.95, respectively. 2) Refractive error and corneal radius, corneal power, lens thickness were correlated with the correlation coefficients for 0.60, 0.66, 0.67 respectively. 3) There were no significant correlation between refractive error and corneal thickness.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.22 no.9
• /
• pp.1957-1967
• /
• 1997

Adaptive channel equlization accomplished without resorting to a training sequence is known as blind equalization. In this paper, in order to reduce the speed of the convergence and the steady-state mean squared error simultaneously, we propose the multi-stage RD(radius-directed) algorithm derived from the combination of the constant modulus algorithm and the radius-directed algorithm. In the starting stage, multi-stage RD algorithm are identical to the constant modulus algorithm which guarantees the convergence of the equalizer. As the blind identical to the constant modulus algorithm which guarantees the convergence of the equalizer. As the blind equalizer converges, the number of the level of the quantizers is increased gradually, so that the proposed algorithm operate identical to the radius-directed algorithm which leads to the low error power after the covnergence. Therefore, the multi-stage RD algorithm obtains fast convergence rage and low steady stage mean square error.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.24 no.3
• /
• pp.448-458
• /
• 2020

Indoor positioning based on trilateration using common chord estimates location of a mobile subject by using intersection points between each circles which the radius is same as distance between the mobile subject and each radio-frequency transmitter. However, if the intersection points are not found due to error of the distance measurement, it causes failure of estimating the mobile subject's location. To prevent this case, numbers which is proportionate to radius of each circles, are temporarily added to each distances in order to lengthen radius of the circles. Although the estimated location includes error due to the radius extension, it is corrected again by the added value and distance from reference point. With introduction of the advanced correction algorithm, potential issues of existing trilateration such as failure of estimating location and distance measurement error will be minimized.

• Journal of the Korean Society for Precision Engineering
• /
• v.7 no.3
• /
• pp.37-47
• /
• 1990

In accordance with the high precision of mechanical elements, it has been required to high precision in surface roughness measurement and, therefore, stylus tip radius is manufa- ctured less than 2 .mu. m through ion sputter machining. In this experiment, by suing ion sputter machined stylus pf fine tip, radius and lapping machined stylus, surface roughness of standard specimens, silicon wafer were measured and then Rmax, Ra, RMS value were investi- gatedaccording to the variation of tip radius of stylus. As a result, measuring error due to the variation of stylus tip radius in surface roughness measurement was decreased by using ion sputter machined stylus and also the measuring accuracy was improved. And the measuring variation of Ra, RMS calculated from correlation coefficient lager than 0.9 on the wave of short period and amplitude using ion sputter machined stylus of fine tip radius.

• Transactions of Materials Processing
• /
• v.13 no.1
• /
• pp.90-101
• /
• 2004

An inverse mosaic method has been proposed to generate an initial blank shape from the final product shape. Differently from the geometric mapping method, the method can handle triangular patches. However, the generated blank shape is strongly dependent on the order of determination of nodes. In order to compensate the dependency error smoothing technique has been also developed. Although the accuracy has been improved greatly compared with the geometrical mapping method, the method has limitation, due to the no incorporation of plasticity theory. Even though the accuracy of the radius vector method is already proved. the method requires initial guess to start the method. In order to compromise the limitation of the present method and the radius vector method, the method has been connected to the radius vector method. The efficiency of the present optimal blank design method has been verified with some chosen examples.